Apparatus for mixing viscous liquids



Dec. 1959 MAXOTTO SCHURMANN 2,917,

APPARATUS FOR MIXING VISCOUS LIQUIDS Filed Sept. 26, 1956 mm W INVENTOR. MAX OTTU SCHURMANN A TTORNEYS United States Patent APPARATUS FOR MIXING VISCOUS LIQUIDS Max-Otto Schiirmann, Dormagen, Germany, assignor to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany Application September 26, 1956, Serial No. 612,242 Claims priority, application Germany October 10, 1955 3 Claims. (Cl. 259-7) The present invention relates to apparatus for mixing viscous liquids.

A large number of different apparatus have already been proposed for continuously mixing viscous liquids, including inter alia those of cylindrical form, in which there is arranged axially of the cylinder a rotating shaft having fixed thereon a plurality of circular perforated discs which alternate with stationary perforated discs secured to the housing, the medium to be mixed flowing through the said discs in a direction parallel to the axis. The principle of this so-called perforated disc mixer produces an excellent mixing action. Furthermore, dead spaces are substantially avoided with this arrangement. The production of a larger output is, however, counteracted by the fact that the number of discs arranged one behind the other (alternately fixed and rotating discs) cannot be increased as desired, because then assembly and adjustment meet with insurmountable difficulties.

This difficulty is overcome by the apparatus according to the present invention, in which the liquid flows radially instead of axially. In such a case, it then passes successively and alternately through a rotating annular screen and one which is fixed or is rotating in the opposite direction. Since the annular screens with the same direc-' tion of movement can all be mounted on a common (llSC,

and the fixed annular screens can be mounted on the opposite housing wall, the arrangement can'be assembled by simply fitting one part within the other. The apparatus for mixing viscous liquids in a continuous process permits very homogeneous mixing within the shortest possible time, owing to the intensive action taking place over the entire internal space of the apparatus, thus avoiding dead spaces, this being in contrast to most of the known arrangements. In certain circumstances, the apparatus can with advantage be used for mixing any kind of substance, such as matting agents or dyestuffs, withviscous spinning masses for the purpose of producing artificial fibres. Embodiments of the invention are shown diagrammatically in the drawing.

Fig. 1 is a sectional view of a mixing apparatus having oppositely disposed intermeshing annular screens;

Fig. 2 is a top view diagrammatic section of the apparatus of Fig. 1;

Fig. 3 is a sectional view of an apparatus similar to that of Fig. 1 having oppositely rotating screens;

Fig. 4 is a sectional view of a mixing apparatus having intermeshing fixed and rotating double screen members;

Figs. 5a and 5b illustrate details of the screen members.

Figures 1 and 2 are respectively a longitudinal section and a cross-section through a mixing apparatus, with a fixed series of annular screens and a movable series of annular screens as well as a central supply means and "ice tangential discharge for the mixed material. The material enters the pipe of the housing at a. The lower part of the housing carries annular screens b, opposite which are annular screens d fixed on the rotating disc 0.

5 The outlet is shown at e.

Figure 3 shows an apparatus with two oppositely rotating series of screens. In this arrangement, the material enters through a hollow shaft at a and discharges laterally at 2.

Figure 4 is a section through an arrangement comprising two fixed screening members I and a rotating double screening member g. The inlet and outlet are both centrally arranged in this case. The arrangement has the advantage that the mass is subjected to twice the number of treatment stages in passing once through the apparatus. The arrangement shows another type of construction, in that the height of the screening frames and housing decreases with increasing diameter. The result thereby obtained is that the average volume remains substantially constant. The formula 21rr.h=constant can form the basis of the calculation. In the formula 21rr.h=constant, r designates the radius of the circular perforated disc and h the height thereof.

Perforated or slotted metal sheets, or wire screens, can be used as such or in combination as the screening members. One particularly advantageous form as regards flow resistance and mixing effect makes use of inclined slots which are alternately inclined towards the right and the left, preferably by an angle of approximately 45 (Figures 5a and 5b).

I claim:

1. Apparatus for continuously mixing viscous liquids comprising inter-meshed screening surfaces which are movable relatively to one another in a housing, which surfaces are successively traversed by the material to be mixed, wherein the screening surfaces are bent to circular form and are arranged concentrically of one another and wherein the height of the screening surfaces and the housing decreases with increasing diameter in accordance with the formula 27rr.h=constant, in which formula r is the radius of the circle formed by the said screening surface and h is the height thereof.

2. Apparatus according to claim 1, wherein the screening surfaces are arranged edgewise, alternately on a fixed support and a rotatable support.

3. Apparatus according to claim 1, wherein some of the screening surfaces are fixed edgewise on two opposite- 1y arranged stationary supports in such a way that their edges which face one another form a space in which is rotatably arranged a support having the other screening surfaces disposed edgewise on its top and bottom sides, the supply and discharge means for the material being disposed in the direction of the axis of rotation.

References Cited in the file of this patent 1 UNITED STATES PATENTS Germany July 11, 1913 

